Myron Bander

Unparticles: Scales and high energy probes

Unparticles from hidden conformal sectors provide qualitatively new possibilities for physics beyond the standard model. In the theoretical framework of minimal models, we clarify the relation between energy scales entering various phenomenological analyses. We show that these relations always counteract the effective field theory intuition that higher dimension operators are more highly suppressed, and that the requirement of a significant conformal window places strong constraints on possible unparticle signals. With these considerations in mind, we examine some of the most robust and sensitive probes and explore novel effects of unparticles on gauge coupling evolution and fermion production at high energy colliders. These constraints are presented both as bounds on four-fermion interaction scales and as constraints on the fundamental parameter space of minimal models.

Theories of quark confinement

Abstract It is conjectured that a non-Abelian gauge theory based on the color SU(3) group will confine quarks. Various techniques that have been applied to this question are reviewed. These include approximate methods based on strong coupling expansions of Hamiltonian and Euclidian lattice theories, instanton improvements on perturbation theory, and solutions of truncated Dyson-Schwinger equations for the gauge field propagator. Formal results based on electric-magnetic duality arguments and on the study of loop field theories are presented. Deconfinement at high temperatures, the inclusion of light quarks, and a possible reconciliation with a hypothetical discovery of free quarks are discussed.

Equations of motion for spinning particles in external electromagnetic and gravitational fields.

The equations of motion for the position and spin of a classical particle coupled to an external electromagnetic and gravitational potential are derived from an action principle. The constraints ensuring a correct number of independent spin components are automatically satisfied. In general the spin is not Fermi-Walker transported nor does the position follow a geodesic, although the deviations are small for most situations.

Gravity in dynamically generated dimensions

Author(s): Bander, M | Abstract: A theory of gravity in (Formula presented) dimensions is dynamically generated from a theory in d dimensions. As an application we show how N dynamically coupled gravity theories can reduce the effective Planck mass.

Proton β decay in large magnetic fields

Abstract Both electromagnetic and strong interactions contribute to make, in magnetic fields of the order of B > 1014 T, the neutron stable against beta decay and for somewhat larger fields the proton becomes unstable to a decay into a neutron via β emission. Changes in chiral condensates due to such fields and an unexpectedly large field dependence of hadronic magnetic moments would modify these arguments. Fields of such magnitude may exist in colliding neutron stars and in the vicinity of cosmic strings. Possible astrophysical consequences are discussed.

Random surfaces with a curvature-dependent action large-D expansion

Abstract The action for discretized random surfaces imbedded in a D -dimensional space is generalized to include curvature. The effects of this term on the Hausdorff dimension, d H , of the surface is investigated in a mean field or large- D approximation. To order 1/ D neither the area part of the action nor the curvature part change the leading result, namely d H = ∞.

Large magnetic field instabilities induced by magnetic dipole transitions

Abstract We present a new mechanism that will limit very high magnetic fields which have been conjectured to exist in connection with some astrophysical phenomena. Low lying strongly interacting particles and resonances mixing with each other via magnetic dipole QED couplings force a vacuum instability for large external magnetic fields. These mixings limit fields to a few GeV 2 .

Flavor changing neutral processes and Bd0−B̄d0 mixing☆

Abstract We propose that the observed B d 0 −B d 0 mixing reported by ARGUS and CLEO is due to the tree-level flavor changing neutral coupling of the standard model Higgs scalar, H 0 , or the Z 0 , induced by new physics with a mass scale beyond the standard model. The strengths of the flavor changing couplings of H 0 and Z 0 are shon to be increasing with the masses of the fermion flavors involved. If the observed B d 0 -B d 0 mixing is due to the flavor changing coupling of H 0 , the key predictions are D D 0 -D 0 mixing of O (10%) of the present experimental upper limit and BR(μ − a e − γ) ≅ (1.1 ± 0.6) × 10 −12 , and the mass of the Higgsscalar M H ≅(200–300) GeV. In case the observed B d 0 - B d 0 mixing is due to the flavor changing coupling of Z 0 , the rare decay mode μ − ae − e + e − is predicted to be observable at any time in the near future with the branching ratio in the neighborhood of the present experimental upper limit, while other predictions include: D 0 -D 0 mixing of O(1–10)% of the present upper limit, BR(B s 0 a μ + μ − X) ≅ (8.5 ± 4.2) × 10 −5 , BR(τ t- a μ − μ+μ − ) ≅ (8.8 ±4.8) × and the branching ratios for the flavor changing decay modes of Z 0 , BR(Z 0 abs + ss) × 10 7 ≅ (14 ±7), BR (Z 0 a tc + ct) × 10 7 ± (1500 ± 700)( m t /60 GeV ), BR(Z 0 a b′b +bb′) × 10 7 ≅ (4800 ± 2300)( m b /50 GeV), BR (Z 0 a μ − τ + + μ + τ − ) × 3.6 ± 1.8, and BR (Z 0 a τ′ τ + τ′τ) × 10 7 ≅ (1300 ± 600) ( m τ /40 GeV). These flavor changing branching ratios of Z 0 can be tested at LEP with 10 7 Z 0 ′s. From the observed strength of B d 0 -B d 0 mixing the scale of new physics can be inferred to be M ≅ 250 GeV.

Screening of very intense magnetic fields by chiral symmetry breaking

Abstract In very intense magnetic fields, B >1.5×10 14 T, the breaking of the strong interaction SU (2) × SU (2) symmetry arranges itself so that instead of the neutral σ field acquiring a vacuum expectation value it is the charged π field that does and the magnetic field is screened. Details are presented for a magnetic field generated by a current in a wire; we show that the magnetic field is screened out to a distance ϱ 0 ∼I ƒ π m π from the wire.

Equivalence of lattice gauge and spin theories

Abstract It is shown that a lattice gauge theory based on the group G is equivalent to a lattice spin theory invariant under a global group which is an infinite direct product of Gs. A method of inducing a lattice gauge theory is presented.